Ball-bearing clamp to hold straightedge on a drafting board



June 13, 1950 2,511,654

D. D. SPOOR BALL BEARING CLAMP TO HOLD STRAIGHT EDGES 0N DRAFTING BOARDSFiled Dec. 13, 1946 v f4 fg 9 f6 Inventor Un/ E l?. POOR ara/awayPatented June 13,. 1950 BALL-BEARING CLAMP 'ro HOLD STRAIGHTEDGE oN ADRAFTING BOARD Dale D. Spoor, Kalamazoo, Mich.

Application December 13, 1946, Serial No. 716,020

2 claims. 1

The present invention relates to improvements lin ways and meansexpressly constructed and adapted to accommodate and shiftably mount astraight edge on a drafting table, drawing board or the like, it beingthe primary object of the invention to structurally, functionally andotherwise improve upon known types of clamps in this field of invention.

Another object of the invention has to do with novel straight edgeclamps and means for mechanically and slidably mounting the same on adrawing board, this in a manner to adjustably situate the straight edgein proper operative relation to the drawing surface of said boardwhether the latter be in a horizontal, vertical or intermediate draftingposition.

A further object of the invention resides in the provision of astructural adaptation which lends itself particularly applicable andcommercially satisfactory and efficiently adaptable to requirements ofthe trade and the user under virtually all conditions and circumstances.

A still further object of the invention, generally speaking, is toimprove upon and reduce the number of elements and parts which enterinto the complete combination, thereby not only increasing resultfulnessand the efliciency of the structure as a whole, but also rendering sameless costly to manufacture, and to otherwise simplify factors ofassembling, sale and reliable usage.

In addition to the above and considered from a structural and functionalpoint of view, an added object of the invention is to provide simplegrooved bars, these beingattached securely to transverse end portions ofthe drawing board, the same serving as tracks, and further providingeffective devices to accommodate special slide brackets, the bracketsfunctioning as carriages on which the end portions of the straight edgeare detachably and adjustably mounted. y

Other objects, features .and advantages will become more readilyapparent from the various views of the accompanying sheet of drawings.

In the drawings, wherein like numerals are employed to designate likeparts throughout same:

Figure 1 is a fragmentary view illustrating a corner portion of adrafting or drawing board, parts being in section and elevation, saidview showing one of the clamps and complemental features thereof.

Figure 2 is an end elevation with portions broken away and shown insection and other parts removed, of Figure 1, observing the latter in adirection from right to left.

Figure 3 is a top plan view of the structure shown in Figure 1.

Figure 4 is a reduced view showing a drafting table, this provided withthe invention herein under advisement.

Figure 5 is a fragmentary end elevation of the structure seen in Figure1 with certain parts removed.

Figure 6 is a perspective of a clip forming a part of the track means.

Reference being had first to the complete illustration in Figure 4, weobserve an ordinary type of drafting table, same including a stand orbase A and a tiltable top, such as will hereinafter be referred toeither as a drafting or drawing board B. The straight edge is denoted bythe numeral 8 and is of a length greater than the length of the board B,the end portions thereof being provided with centralized attaching andadjusting slots 9. Both ends of the straight edge are slotted andadjustably and slidably mounted on the drawing board. In thisconnection, andinasmuch as the structure at each end of the board is thesame, a description of the structure at one one end will suffice forboth.

In carrying out the specific principles of the invention a bar I0,substantially rectangular in cross sectionaliform, and of a lengthcorresponding to the width of a drawing board is provided. As shown inFigure l said bar I0- is secured, by screws or equivalent fasteningmeans Il, to the coacting end portion of the board. It is preferablypositioned so that the bottom surface thereof is substantially iiushwith the corresponding bottom surface of said board. The top and bottomsurfaces of said bar have shallow longitudinal grooves I2 and I3respectively and these serve as track ways. Thus, the grooved barfunctions as a simple track and lends itself admirably Well adapted to asimple and expedient Slide bracket I4. Said bracket It comprises achannel-shaped portion I5 which functions as a shoe and which is mountedupon and shiftable along said track. The particular manner in which theshoe is saddled upon the track is brought out in Figures 1 and 2 and inreference to Figure 1 it will be seen that the upper and lower flangesof said shoe are provided with holes I6 and I1 properly seated toaccommodate anti-friction balls I8 and I9. The web portion of the shoeis provided with appropriate set-screw 20 which serves, whenevernecessary or desired, to bind and fasten the shoe in a predetermined aswell as an established position. In this connection it is well to pointout that by making the parts under precision dimensions, sucientretentive action may be attained between the shoe and track to cause theshoe to remain relatively stationary when placed in a set position andwithout necessarily having to tighten the set-screw 20. The upperportion of the bracket or shoe is of general L-shaped form as at 2l andthe horizontal or upper limb of this is provided with an upstandingscrew-threaded stud 22. The inner end portion of the stud is formed witha substantially rectangular block-like guide and assembling element 23which serves to snugly accommodate the coacting slot 9.

The numeral 24 designates a washer surrounding the stud, 25 a coiledspring, and 26 a knurled nut on the stud which serves to properlytension and regulate the spring. It is thus thatthe slotted end of thestraight edge is detachably and adjustably assembled.

Reference being had now to Figure 2, the nu- Ameral ,2l designates .acleat/or clip.=which is .-secured by a fastening 28 to oneend .oftheAbar yin a manner tofclosethe adjacent lopen endsof -the trackwaygrooves. Theopposite ends Vof .said grooves are closed in at the time ofmanufacture.

l -It :will be evident thateby slidably bracketing ,the-eend :portionsof va straight edge .to the .transverse ends of a drawing board andsaddlingJ-the brackets over simple gtrack bars, -a structural adaptationis thus provided 4whereby thevstraight vedge is `constantly Yon theboard .and .is AeverV in readiness V`for useV .when needed and forplacement at an out-of--the-way position when A,not needed. The use of.ball bearing brackets, and :tracking supporting-.means provides what Yisbelieved to .bean exclusive and ideal Ameansaccoinplishing the endsdesired.

.low the top .of said board, a.- one-.piece longitudinallyshiftableadaptor Vbracketincludinga chan.- nel-.shaped .portion.constituting ashes, said shoe partially encasing, -.tting.ovenandboingslidable .back .and forth on said bar, saidshoeembodyng top and.bottom Vflanges provided with freely rollable ball hearings, `thetopand bottom surfaces of .said bar ,beingprovided .with `open-,endedchannels vproviding trackways for `said ,ball bearings,

Ythe latter Vbeingseated in said tramways. Ysaid brackets including anYI -shaped upstanding por- `tion having its Vh orizoiital limb parallelto and ,above the `top flange of theshoe and located on a planesubstantially ush with the top surface of said board and equipped withan upstanding screw-threaded stud carrying a nut to accommodate, ifdesired, a member which may be slidably mounted for shiftable movementon said board, and end cleats removably mounted on the opposite endportions of said bar and closing the open ends of the respectivechannels.

2. An anti-friction slide structure of the class shown and describedcomprising a board having a flat top susceptible of use, as desired, asa drafting board, a bar detachably screwed to one marginal .edge portionof said board, said bar being substantially rectangular in crosssection, the top and bottom surfaces of said bar having openendedchannels providing trackways for freely rollable ball bearings, thebottom surface of said bar being flush with the bottom of the board andthe top of said bar being on a plane below the top surface v,of ,saidv.board,a ,onepiece .longitudinally shiftableadaptor .bracket includingachannelshaped .portion vhaving top and bottom anges A.and .abightconnecting said flanges, saidchannel-shaped portion, L Jartiallyencasing and vfitting Overandbeing slidable baokandforth on said bar.and `oonstifailtins .an antifriction slide, .anti-friction ballsmounted for free rotation 4in the top ,andv bottom .danses and situated.mand rollable back .and .forth .in .Said trackways, said bracket.including aninverted .lfshaped portion 'having yhorizontal and verticalllirrhibstlae horizontal limb beingin .spaced .parallelism above .thetop danse .of Saidboe- .and being 'in aplane .substantially flush withythe .dat top of .Said board-and orovided with an upstandingscrew-.threaded stud, an assembling and retaining nut carried by saidstud, a Set screw carried by .Said bight and .re-

4leasably engageable with a coacting. surface of said bar, vand a pair,of end cleats removably Amounted on vthe oppositeend portions of saidbar and having their respective end portions lined up with y,and closingthe .end portions .of said channels DALE D. SPOOR.

' REFERENCES CITED T .he following references lare vof record in .the le.of .tbispatentt UNITED STATES PATENTS Number Name Date 429,586 SajousJune 3, 1890 1,045,523 Cossey Nov. 26, 1912 1,183,977 Hoee May 23, 19161,4&3,998 Meltzer Feb. 6, 1923 1,5 84-,839 Cameron May 18, 1926115095379 Morris Dec. 7, 1926 2,370,861 Jakeway Mar. 6, 1945 YVllOREIGrNPATENTS Number Country Date A531,850 YGermany Aug. 31,1931

